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JOSEPH W.- STOW, OF SAN FRANClSCO, CALIFORNlA.

Letters Patent No. 113,702, dated April 1-1, 1871.

IMPROVEMENT IN THE MANUFA-CTURE OF PNEUMATIC GAS FOR ILLUWHNATING, gcc.

The Schedule referred to in these Letters Patent and makingvpart of thesame.

To all whom it may concern:

Be it known tirati, JOSEPH W. S'row, of San lranf cisco, in the countyof San Francisco and`iu the State of California, have4 invented anImprovement in the Manufacture of Pneumatic Gas, oi' which the followingis a specification, reference being had to the accompanying drawing.

ln the manufacture of illuminating-gas from gasoline orsimilarhydrocarbons lgreat diiiiculty has been experienced in obtaininggas of a uniform quality in consequence of, iirst, the difierence in thespecific gravity of the gasolihe,as the rapidity with which it(gasoline) vaporizes at'agiven temperature depends verymuch upon itsdensity ,'and, second, even though a gasoline of uniform standard beemployed, and the carbureter be maintained at an unchanged temperature,it is always found that the more Volatile portions are given off first,making a very richgas; but, as the process of carburetiug goes on, theevaporation becomes less frc'e, so that, as the bulk of gasoline isreduced, the gas gradually becomes poorer.

The method usually adopted to attain a uniformity. in the quality hasbeen to control the vapor-ization of the gasoline by regulating thetemperature of either v the gasoline itself or of the air which wasbeing passed .through it.

Another method has been to add atmospheric air to the gas after it hasbeen `produced in such quantities as should reduce it (the gas) to thedesired photometric standard. But these moans, as they have beenheretofore employed, have failed to accomplish the desired end.

It has been found entirely impracticable to regulate the temperaturesatisfactorily, and the manner in which air has been introduced isobjectionable for two reasons:

First, it permittedcondensation to take place in the pipes, which isvery objectionable; and

Secondly, it failed to produce a uniform quality of gas at all points,this latter "defect arising from the imperfect diffusion or mixing ofthe air with the gas.

The invention relates to that class of machines or works io which air isforced through or over the gasoline at such a temperature as .shallinsure a gas richer in carbon than is required for illuminatingpurposes, and is designed to overcome the above-recited diihculties, andto accomplish the manufacture of a gas which shall not be subject tocondensation under such changes of temperature as it shall ordinarily besubjected to, and shall be of uniform density and photometric quality,itc this end f The invention consists in introducing or adding to andcombining with the carbureted air such portion of atmospheric air asvmay be desired,andintimately mixing or diiusing the same throughout thegas by means of certain devices, as wilt be hereinafter fully explained.

Figure l is a longitudinal vertical sectionrof a pneumatic gas apparatusembodying myinvention.

Figures 2, 3, 4, 5, and 6 .represent various devices by the aid of whichmy invention may be carried into effect.

Each part is distinguished by the same letter wheuv ever it appears inthe drawing.

A is a tank closed at top and bottom.

Through the center of the tank A passes a verticaltube, B, communicatingat its upper end with the pi pc 0and at its lower end with the spaceat'the under side of the perforated false bottom D. The tanks E and llrepresent an ordinary gas-holder.

The tank` A communicates with the interior ofthe gas-holder by means ofthe pipe G.

It' the gas-holder be supplied with water and the tank A with somesuitable liquid hydrocarbon, and atmospheric air be forced down throughthe tube B, under the perforated plate, up through the liquidhydrocarbon, and, through the pipe G, to the interior of the gas-holder,the ordinary mixture of'air and vapor, known and used as pneumatic gas,will collect above the surface of the water in theinterior of the tankE. yThe constantly varying/'proportions of th'e ingredients and lack ofpermanency of this mixture have been' hereinbefore set forth, as well asthe inconvenience .and waste attending its use if too highly chargedwith vapor.

When my invention is employed the mixture may be supplied from the tankA, with as large aproportion. of Vapor as possible, and an additionalquantity of lair is regularly supplied to and incorporated with it inthe tank E, just sniiicient in quantity to secure and constantlymaintain the proper uniform proportions oi' the ingredients, in orderthat no condensation may take place in the distributing-pipes, no wasteof carbonoccur, andthe most economicalv production of light or heat isobtained, constant in quantity and quality for a given bulk. rl'lhisadditional supply of air is introduced from the pipe C through the pipeH.

The pipe H is divided into two branches H1 HZ, terminating in aperforated horizontal pipe, H, by which the air entering through thepipe H is discharged in every direction, and becomes intimatelyincorporated with the mixture.

When hot air is to be admitted through the pipe H the branches Hl H2should be protected from contact with the water. The sleeves or outerpipes I are pro vided for that purpose.

Instead of the branches H and Hzaudthe straight pipe H3, the pipe H mayterminate in the center of the gas-holder and in arms H, and dischargethe air -thioliglfthe perforations of the endless pipe H5, figs. 42 and3, or may terminate in the rose H6, iig. 4.

, Heat may bejapplied to the pipe H at J, or the pipe H may bedivided-and connected with each end of la coil of pipe passing through afurnace; or the air passing through the pipe H may be heated in anyconvenient manner.

Although the addition and incorporation of coldI air will accomplish, toa certain extent, the various objects of my invention, the addition andincorporation of hot air, in the manner herein described, will producepneumatic gas that at any'given temperature will retain a much largerproportion of carbon than would be retained at that-temperature by anypneumatic gas produced by the ordinary process or system without myinvention, or by any pneumatic gas produced by my improved processwithout heating the air.

The pipe C may receive its supply of air from a fan driven byasteam-engine, or from any suitable blowv satisfactorily, because .theaddition has been made'dur.-

ing'thepassage of the gasthrough the mains or Aserrvice-pipes7 and theproportions could .not be properly regulated,.nor lcould a thoroughdiffusion be effected, for which reason aninferior quality of gas wasproduced, and more or less condensation wouldtake place in the pipes;but I have found, by repeated and thorough trials,othat, by mixing theair with the gas in a large gasometer, into which the air is introducedthrough a rose or perforated coil` of pipe, audin which a thorough andintimate difg'usion and assimilation takes place, I am enabled tomanufacture a gas of uniform density, and which is not subject tocondensa.- tion under any pressure or change of temperature to which itis ever subjected inY ordinary practice.

assimilation by means of these devices, whereby the mixing can takeplace while thel gas is in astate-of comparative rest, and when therequired length of time can be allowed, I can largely increase thequantity of gas produced-from a given amount of gasoline, as I can addfrom two hundred to four hundred per cent. of atmospheric air to thecarbureted air without reducing the standard of-its photometric value.

I am also aware that attempts have been made to improve ordinarycoal-gaslb'y combining with it carbureted air; therefore I do not claim,broadly, either the 4combination of two or more illuminating-gases, northe addition of atmospheric air to air which has .been previouslycarbureted; but f The herein-described method ofzcombining atmosphericair and carbureted air by means of the devices described.

In testimony whereof I have hereunto set my hand this25th day ofOctober, A. D. 1870.'

' J. W. S'IOW.

Witnesses W. H. DIMonD, WM. B. Isaacs.

I have found that, by effecting this diffusion and

